Starter fob internal-combustion



June 13, 1950 o. L. MILLER STARTER FOR INTERNAL-COMBUSTION ENGINES Original Filed May 3, 1945 \1 u u UHH WNHHHHWTWK M I w INVENT OR. 5 a

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Patented June 13, 1950 UNITED STATES PATENT OFFICE STARTER FOR- INTERNAL-COMBUSTION ENGINES Original application May 3,

1945, Serial No.

591,655. Divided and this application April 29, 1946, Serial N0. 665,704

4 Claims.

The present invention relates to a starter for internal combustion engines and more particularly to that type in which operative engagement of the drive is maintained until the engine is reliably self-operative.

This application is a division of the parent application of Donald L. Miller, Serial 591,655, filed May 3, 1945, now matured into Patent No. 2347,198, issued August 17, 1948.

It is an object of the present invention to provide an engine starter incorporating a novel over-running connection for actuating the starter pinion, such connection being arranged to drive positively and without localized stresses, and to overrun quietly.

It is another object to provide such a device in which the over-running connection is arranged to be normally disengaged, and only brought into engagement when power is to be transmitted therethrough.

It is a further object to provide such a device in which a predetermined frictional drag or torque transmission is incorporated in the overrunning connection so as to insure reengagement of the connection after disengagement due to a false start, and also to insure proper disengagement of the drive upon deenergization of the starting motor.

It is a further object to provide such a device in which the frictional drag of the over-running connection may be automatically increased in accordance with the speed of rotation of the device.

Further objects and advantages will be apparent from the following description taken in connection with the accompanying drawing, in which:

Fig. 1 is a side elevation partly in section of a portion of a starting motor and control mechanism therefor comprising a preferred embodiment of the invention, the remaining elements of the starting system being indicated diagrammatically;

Fig. 2 is a similar view of the opposite end of the starting motor with the drive mounted thereon; and

Fig. 3 is a detail in perspective, partly broken away, of the overrunning clutch assembly.

In Fig. l. of the drawing there is illustrated a. starting motor I having an armature shaft 2 which is slidably journalled in the frame of the starting motor whereby it may be moved longitudinally so as to decenter the armature with respect to the motor field. Means for energizing the starting motor are shown comprising a battery 3 grounded at 4 and connected by a lead 5 to one terminal 6 of a starting switch indicated generally by numeral 1. A second terminal 8 of the starting switch is connected by a lead 9 to the starting motor, indicated diagrammatically at SM, which is grounded at H to complete the starting circuit. A bridging contact I2, mounted on a magnetic plunger i3, is arranged to connect the switch terminals 0 and 8 to close the starting switch when actuated by a solenoid H, a spring I5 being provided to normally hold the switch open. Means under the control of the operator for energizing the solenoid l4 are provided comprising a lead 16 connected with the battery lead 5, a manual switch I! connected to the solenoid by a lead 18, and a ground connec tion 19.

A second plunger of magnetic material 2! is slidably mounted in the solenoid l4 and is provided at its lower end with a cam head 22 which enters the end bearing 23 of the starting motor in position to engage a thrust block 24 bearing on the end of the armature shaft 2. The plunger 2i is normally projected by a spring 25 into the position illustrated in Fig. l where the armature shaft has been cammed into its displaced or decentered position, and positively locked therein by engagement of the thrust block 24 with the side of the plunger head 22.

A casing 26 is provided for enclosing and supporting the magnetic starting switch and the shifting and locking means, the casing being attached to the starting motor and bearing 23 in any suitable manner as indicated at 21.

The opposite end of the armature shaft 2 is provided with a smooth reduced extension 28 as illustrated in Fig. 2 on which is slidably journalled a pinion 29 that is adapted to mesh with and rotate a gear 31 of the engine to be started.

A driving sleeve 32 is fixed on the end of the armature shaft as by means of a pin 33, and has slidably journalled thereon a screw shaft 34 retained thereon by a lock ring 35. The screw shaft is yieldably connected to the sleeve for longitudinal and rotary movement by means of a drive spring 36 and anchor plates 31 and 3B.

A driving clutch member 39 is threaded on the screw shaft and provided with teeth 4| arranged to engage corresponding teeth 42 on a driven clutch member 43 rigidly mounted as indicated at 44 on the pinion 29. Means for limiting the separation of the clutch members 39, 43 is provided comprising a sleeve 45 fixed to the driving clutch member as shown at 46. and having an inturned flange 41 adapted to engage the driven clutch member when the clutch members are separated sufficiently to provide clearance between the teeth 4| and 42.

Spring means tending to separate the clutch members is provided in the form of a fiat spring member 48 (Fig. 3) attached to the driven clutch member 43 at one end as shown at 49 and tensioned to spring outwardly against the interior of the sleeve 45. Said sleeve is provided with a tapered portion 5| adjacent the spring 48 whereby when the clutch members are engaged the spring bears on the tapered portion and thereby tends to separate the clutch members. The spring 48 is also arranged to serve as a frictional torque transmitting member between the two clutch members whereby a proper amount of control is established to secure reengagement of the clutch members after a false start and to transmit rotation from the pinion to the driving cluch member 39 to secure demeshing of the pinion after the engine has started. The clutch member 39 may be normally retained in its idle position as illustrated by any suitable form of anti-drift detent such as indicated at 50.

In operation, starting with the parts in the positions illustrated, closure of the manual switch l1 energizes the solenoid M which closes the starting switch and also withdraws the plunger 2| against the action of spring 25. The energization of the starting motor causes the armature thereof to center itself, thus moving the armature shaft 2 to the left sufficiently to enter the ends of the teeth of the pinion 29 into the tooth spaces of the engine gear 3|. At the ame time, rotation of the armature shaft 2 is transmitted through the yielding connection 36 etc. to the screw shaft 34, whereby the driving clutch member 39 is threaded to the left, pushing the pinion along the armature shaft until it engages the shoulder 52 formed by the reduction in diameter thereof. When this occurs, the pinion is fully meshed with the engine gear and the further movement of the driving clutch member 39 causes the teeth 4| thereof to be forced into driving engagement with the teeth 42 of the driven clutch member 43 whereupon a positive driving connection is established from the clutch member 39 to the pinion. The screw shaft 34 is thereby forced backwardly to the right, compressing and loading the drive spring 36 until sufficient torque has been built up to cause rotation of the engine gear to crank the engine.

When the engine fires, the acceleration of the pinion 29 is transmitted through the clutch teeth 42, 4| to the threaded clutch member 39 which consequently threads itself back on the screw shaft 34 and disengages the clutch teeth. The pinion is kept in engagement with the engine gear 3| by reason of the centered position of the armature shaft 2, and overruns its driving connection freely and quietly since the spring 48 holds the clutch members disengaged.

Should the engine fail to continue self-operative, the consequent deceleration of the pinion 29 permits the starting motor to catch up with it, whereupon, due to the frictional drag of the spring 48, the driving clutch member promptly threads itself to the left on the screw shaft, movin the pinion into full mesh and closing the clutch, whereupon cranking is resumed. When the engine is reliably self-operative, the operator opens the manual switch l1, thus deenergizing the solenoid and permitting spring |5 to open the starting switch and springs 25 and 55 to project the plunger 2| so as to overcome the effect of the detent 53 and cam the armature shaft 2 into its idle or displaced position.

Although but one embodiment of the invention has been shown and described in detail, it will be understood that other embodiments are possible and that variations in the design and arrangement of the parts may be made without departing from the spirit of the invention as defined in the claims appended hereto.

What is claimed is:

1. In an engine starter at power shaft, a pinion slidably journalled thereon, a screw shaft connected to the power shaft for rotation therewith, a clutch member fixed to the pinion, a cooperating clutch member threaded on the screw shaft, means mounted on one of the clutch members for limiting the separation of the clutch members, spring means mounted on the other clutch member cooperating with said limiting means to yieldably hold the clutch members out of engagement and to provide a frictional coupling there-between, and an abutment on the power shaft limiting the meshing movement of the pinion thereon.

2. In an engine starter a power shaft, a pinion slidably journalled thereon for movement into and out of mesh with a gear of an engine to be started, a screw shaft mounted on the power shaft and yieldably connected thereto, a toothed clutch member threaded on the screw shaft, a

corresponding clutch member fixed to the pinion,

a sleeve fixed to one of said clutch members and forming an abutment for the other clutch member so as to limit the separation thereof, a spring mounted on the other clutch member cooperating with said sleeve to normally hold the clutch members out of engagement while frictionally transmitting torque from one to the other, said shaft having an abutment limiting the meshing movement of the pinion thereon whereby the final 7 meshing movement of the threaded clutch member causes it to engage and connect positively with the pinion clutch member.

3. An engine starter as set forth in claim 1 including further, means responsive to centrifugal force for increasing the eifectiveness of the frictional coupling between said clutch members.

4. An engine starter as set forth in claim 2 in which said sleeve has a flared portion cooperating with the spring to urge the clutch members out of engagement, and a cylindrical portion in which the spring bears frictionally to transmit torque, the arrangement of the spring and sleeve being such that the expansive pressure of the spring in the sleeve is augmented by centrifugal force when the parts are rotated.

DONALD L. MILLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,394,531 Buxton Feb. 12, 1946 2,396,986 Buxton Mar. 19, 1946 

